An Attack on the Goodness of God
When you look at the story of the children of Israel in the book of Exodus and throughout the Old Testament, the people of God often seem sort of whiney; there’s a lot of grumbling and complaining. I think most parents can relate to what it’s like for God as a father to relate to the children of Israel.
We need to find ourselves in that story as well because we have a lot of complaints about life—a lot of areas of discontent. We tend to grumble about small, insignificant things. One of the things that’s important for us to do for our own sanctification is to ask the question, “Why am I grumbling and complaining about this?” Usually it’s because I have some idol that I have set up as something that’s very important to me—my own schedule and things that make life better for me. Then when something gets in the way of what makes my life better for me, I am very quick to complain about it.
It is really important to recognize that all of our complaining is ultimately directed against God, whether we mention him specifically in our complaints or not. All of our complaining goes to him; he is the great God. He is the one who exercises his sovereignty over whatever happens. So all of our complaints go right to the top.
That shows what a great sin complaining really is: an attack on the goodness of God.